Most fish contains mercury, so it's better to play it safe and only eat fish occasionally.
: The benefits of eating fish outweigh the risks. A study shows that the death rate from heart disease was 36 percent lower among people who ate fish twice a week compared with people who ate little or no seafood. Nearly all fish contain minute amounts of mercury, but among commercially available fish and shellfish in the North America, the most commonly eaten species (such as shrimp, canned light tuna, salmon, and Pollock) are generally low in mercury and pose little risk to most people. On the plus side, seafood is a rich source of the essential omega-3 fatty acids that have been shown to enhance brain and eye development of the foetus, promote a healthy pregnancy, aid thinking and learning during childhood, reduce the risk of heart disease and stroke, and slow mental decline as people age.